package org.apache.maven.model.superpom;

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.Map;

import org.apache.maven.model.Model;
import org.apache.maven.model.building.ModelProcessor;
import org.codehaus.plexus.component.annotations.Component;
import org.codehaus.plexus.component.annotations.Requirement;

/**
 * Provides the super POM that all models implicitly inherit from.
 *
 * @author Benjamin Bentmann
 */
@Component(role = SuperPomProvider.class)
public class DefaultSuperPomProvider implements SuperPomProvider {

  /**
   * The cached super POM, lazily created.
   */
  private Model superModel;

  @Requirement
  private ModelProcessor modelProcessor;

  public DefaultSuperPomProvider setModelProcessor(ModelProcessor modelProcessor) {
    this.modelProcessor = modelProcessor;
    return this;
  }

  public Model getSuperModel(String version) {
    if (superModel == null) {
      String resource = "/org/apache/maven/model/pom-" + version + ".xml";

      InputStream is = getClass().getResourceAsStream(resource);

      if (is == null) {
        throw new IllegalStateException("The super POM " + resource + " was not found"
            + ", please verify the integrity of your Maven installation");
      }

      try {
        Map<String, String> options = new HashMap<String, String>();
        options.put("xml:4.0.0", "xml:4.0.0");
        superModel = modelProcessor.read(is, options);
      } catch (IOException e) {
        throw new IllegalStateException(
            "The super POM " + resource + " is damaged" + ", please verify the integrity of your Maven installation",
            e);
      }
    }

    return superModel;
  }

}
